From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
> I don't think the inability to cancel all session at once cannot be a
> reason not to not to allow operators to cancel a stuck session.
Yeah, I didn't mean to discount the ability to cancel queries. I just want to confirm how the user can use the
cancellationin practice. I didn't see how the user can use the cancellation in the FDW framework, so I asked about it.
We have to think about the user's context if we regard canceling commits as important.
> > Furthermore, FDW is not cancellable in general. So, I don't see a point in
> trying hard to make only commit be cancelable.
>
> I think that it is quite important that operators can cancel any
> process that has been stuck for a long time. Furthermore, postgres_fdw
> is more likely to be stuck since network is involved so the usefulness
> of that feature would be higher.
But lower than practical performance during normal operation.
BTW, speaking of network, how can postgres_fdw respond quickly to cancel request when libpq is waiting for a reply from
adown foreign server? Can the user continue to use that session after cancellation?
Regards
Takayuki Tsunakawa